Download Ipomoea indica

Ipomoea indica
(or Pharbitis congesta) Noasagao
Copyright 1998-2004 Yoshiaki Yoneda
This species is widely distributed from subtropical to tropical zones. In Japan it is
observed on Hatizyo-zima Island, off the southern coast of Kii peninsula, in Sikoku,
Kyushu, and Yakushima, and it grows thick on Okinawa. Greatly different from
Ipomoea nil, Ipomoea hederacea and Ipomoea purpurea, this species has almost no
self-fertilization and so grows vegetatively, extending thick stems and flourishing
leaves. The near-absence of self-fertilization is due its to self-incompatible genes.
Thus far the author has collected materials from Hatiizyo-zima Island, Hino-misaki
point in Wakayama Prefecture, Muroto-misaki point in Koti Prefecture, Sata-misaki
point in Kagoshima Prefecture, Isigaki-zima Island, and Iriomote Island, as well as a
strain from Guangzhou city in China. These local varieties were crossed with each other
and the hybrids bore seeds and fruits well. When Ipomoea indica is used as a female
parent and crossed with species to which it is closely related, the pollen of both
Ipomoea nil and Ipomoea purpurea are able to germinate. However, although the pollen
tube of either species can enter the styles, the tube cannot elongate more than halfway
into the length of the styles. On the other hand, the pollen of Ipomoea hederacea
germinated and entered into the style, and the pollen tubes elongated to reach
fertilization finally. An interspecific hybrid embryo was recognized after the fifth day of
crossings. However, this embryo stopped embyogenesis afterwards, and collapsed.
Those experimental results were obtained through the work of Mr. T. Fuzisima (former
surname Ooisi).
Ipomoea indica (=Pharbitis congesta)
Slide No. 178-183, 239
Isigakizima Ibarama
Okinawa
hontou Komesu
Hatizyozima
Hatizyozima